SAN DIEGO (Tribune News Service) — The U.S. Supreme Court on Monday agreed to hear a San Diego case dealing with “blind mules,” or people who claim they unwittingly drove drugs across the border, and what type of expert testimony the government can use to convict them at trial.

Stemming from a 2020 criminal case filed in San Diego federal court, the case has major implications for the San Diego region, where federal prosecutors charge hundreds of people each year with illegally importing drugs across the border, often in vehicles at ports of entry. For more than a decade, government officials have acknowledged that Mexican drug-smuggling groups sometimes move their product across the border using unwitting victims, such as commercial truck drivers or those who regularly cross for work and school. But the government maintains that such cases are rare, while defense attorneys contend the use of blind mules is more common than the public realizes or the government will admit.

The case essentially seeks clarification about whether law enforcement witnesses can give general testimony that “most couriers know they are carrying drugs” or if they must limit their testimony to whether a specific defendant knew he or she was transporting drugs. The difference, the petition to the Supreme Court asserts, could significantly make or break a case to a jury.

In this case, the U.S. Attorney’s Office in San Diego accused Moreno Valley resident Delilah Guadalupe Diaz of importing more than 61 pounds of methamphetamine that Customs and Border Protection officers found hidden in the doors of her vehicle. Diaz maintained from the moment of her arrest that she didn’t know about the drugs, telling officers that she was borrowing the vehicle and it belonged to her boyfriend who lived in Baja California.

At trial, in response to questions from prosecutors, a Department of Homeland Security agent testified that drug-trafficking organizations typically don’t use blind mules to move their product because it’s too risky, and that most drug couriers know what they are doing.

“In most circumstances, the driver knows they are hired,” the agent testified. “It’s a business. They are hired to take the drugs from point A to point B.”

Even before the trial began, defense attorneys attempted to bar such statements, arguing that such testimony was too general and offered an opinion about Diaz’s knowledge without addressing whether she actually knew. But the district judge allowed the testimony, and the jury convicted Diaz, who was later sentenced to seven years in federal prison.

After her conviction, Diaz appealed to the 9th U.S. Circuit Court of Appeals, renewing her argument that the DHS agent’s testimony violated the rule of federal evidence that bars an expert from offering an opinion about a defendant’s mental state. A three-judge panel rejected the argument based on 9th Circuit precedent but acknowledged that in other circuits, Diaz would have likely prevailed.

Based on current precedent in the 9th Circuit, federal prosecutors in California and Arizona can introduce the more generalized testimony, making it easier to gain convictions, while federal prosecutors in Texas, which is part of the 5th U.S. Circuit Court of Appeals, cannot elicit such testimony.

The petition asking the Supreme Court to take up the case, filed by Stanford law professor Jeffrey L. Fisher, the co-director of Stanford’s Supreme Court Litigation Clinic, argues that the split in the two courts “is clear and entrenched,” and that the 9th Circuit’s position is wrong.

The petition, which cites previous reporting from the Union-Tribune, argues the 9th Circuit’s interpretation of the evidence rule “lightens the Government’s burden to prove knowledge beyond a reasonable doubt” by allowing sweeping generalizations about a particular class of defendants rather than evidence specific to the actual defendant.

Blind mules

While the DHS agent testified in Diaz’s case that most drivers know when they’re transporting drugs across the border, federal officials have for years acknowledged that not all couriers caught at the border know they’re at the wheel of a drug-laden vehicle.

In 2011, the FBI intercepted conversations between drug traffickers discussing an extensive blind mule operation, which included using a schoolteacher to unknowingly smuggle drugs into El Paso, Texas. The traffickers knew the teacher’s daily patterns, chose her because she was predictable “like a clock” and had access to her car. After she unwittingly crossed the drugs, the traffickers enlisted a locksmith in the U.S. to retrieve the drugs from her trunk without her knowing.

In 2012 and 2013, the U.S. Attorney’s Office in San Diego circulated memos to defense attorneys regarding a rash of blind mule-type cases. In one, recruiters were posting ads in Spanish-language newspapers for drivers who thought they were making earnest wages. Other times, traffickers have used magnets to attach drugs underneath the vehicles of unsuspecting drivers, or replaced normal spare tires with ones concealing narcotics.

In August, a federal jury in San Diego acquitted a man who claimed that he didn’t know about the 50 pounds of drugs hidden inside his car. His defense centered on a six-hour period before he crossed when a friend borrowed his vehicle in Mexico.

“In my experience, (blind mules) are far more common than people realize — and far more common than government experts say,” San Diego defense attorney Ryan Stitt said Monday.

Stitt said it’s hard to determine exactly how often drug traffickers use blind mules. He said that because so many drugs successfully make it across the border, it’s impossible to extrapolate the true number of blind mules from the number of those caught. But Stitt said the blind mule argument is “by far the most common defense.”

Not every blind mule claim is valid, of course. Last month, the U.S. Attorney’s Office in San Diego announced the guilty plea of a woman who concocted fake messages with an accomplice in an attempt to falsely the claim she was a blind mule.

In 2015, San Diego defense attorney Jeremy Warren offered a succinct summary of why traffickers would use unwitting drivers: “You don’t have to pay the guy, he’s not going to be nervous, he’s not going to steal your drugs and he can’t snitch you off.”

The Diaz case is one of about 45 that the Supreme Court has agreed to take on this term. It’s not yet known when it will hear arguments in the case.

Stitt said the Supreme Court could make its own rule, but will most likely side with either the 9th Circuit or 5th Circuit. He said the decision could also have a broader impact and be used in other contexts, such as when law enforcement officers opine on what amount of drugs constitutes a “personal use” versus what amount is likely intended for distribution — a key determination in many drug cases.

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